Doing VPN is like creating a private path from one site to another so that you can transfer data between each other off the untrust network. In order to get VPN tunnel established, IP address of each end must be known. There should be three different cases for VPN setup.
Dynamic Multipoint VPN (DMVPN) is available for at least 10 years I can say. Also, there are many blog posts including Cisco about this topic, but because I am preparing for an exam, I am doing a lab about it then why not share it here for iNET9s’ readers. Introduction to